Electric ignition system for the oven or broiler burner on a gas stove



Jan. 27, 1959 J. L. LUNDGREN 2,370,335

ELECTRIC IGNITION SYSTEM FOR THE OVEN 0R BROILER BURNER ON A GAS STQVE Filed Sept. 6, 1952 "of illustrating the ELECTRIC IGNITIDN SYSTEM FOR THE OVEN OR BROILER BURNER DN A GAS STOVE JohnL. Lnndgren, Rockford, 11]., assignor, by mesne assignments, to Geo. D. Roper Corp, a corporation of Delaware Application September 6, 1952, Serial No. 308,199

2 Claims. (Cl. 161-9) i so constructed and arranged as to minimize the possibility of their becoming faulty in operation.

Another object of this invention is to provide a novel electric ignition system for the oven or broiler burner on a gas stove which may more readily be installed on stoves, thereby reducing the production time of stoves having such ignition systems, and which reduces the possibility of servicing and repair difiiculties resulting from faulty operation.

A further object of this invention is to provide a novel electric ignition system for the oven burner on a gas stove with which may be used standard oven control valves and clock control mechanism interchangeable with v those used on gas stoves not having electric ignition.

Other and further objects and advantages of the present invention will be apparent from the following description of a preferred embodiment thereof, which is shown schematically in the accompanying drawing for the purpose principles andmode of operation of the invention.

Inthe drawing: Figure 1 is a schematic View, with certain parts in section, of an electric ignition system according to the present invention;

Figure 2 is a cross-section through the pressure switch included in the Fig. 1 system; and

Fig. 3 is a fragmentary sectional view through the safety valve.

Referring to the drawing, the main burner 10 is here shown as being of the type which may serve as both an oven burner and a broiler burner, as desired, and is appropriately located within the stove in a known manner for that purpose. In the remainder of this description, the burner 10 will be referred to as an oven burner, although it is to be understood that it is also a broiler burner.

The oven burner 10 receives its gas supply from a manifold 11 which extends along the front of the stove in the well known manner. An oven control valve 12, which may be of the type shown in U. S. Patent 2,303,011, is connected to the manifold 11 and has an outlet 13 lead ing to a conduit 14. As disclosed in that patent, the oven control valve 12 includes a main shut-off valve connected to the control knob 6 to control the flow of gas from the manifold 11. A flow regulating valve 7 is interposed between the valve 5 and the outlet 13 of the oven control valve. The flow regulating valve is moved knob 6, when the latter is turned to a preselected tematent 1O perature setting, and a temperature responsive apparatus 9 including a temperature sensing bulb 9:: adapted to gage the ball 18 to move the latter off its: seat.

temperature within the oven. Conduit 14 is connected to the oven burner safety valve, indicated generally at 15, having an inlet chamber 16, an outlet passage 17, and

a ball valve 18 controlling the flow :of fuel from the.

inlet chamber to the outlet passage. From the outlet passage of the safety valve a conduit 19 leads to the oven burner assembly, which includes an air shutter 20 and a mixer 21. The safety valve '15 is normally closed, with the position ofithe ball valve 18 therein being con trolled thermostatically in response to the ignition pilot burner 22, which is-in igniting relation to the oven burner 10. 1 The operation of the oven burner safety valve 15 is such that the ball 18is seated to block the flow of gas to the, oven burnerexcept while the ignition pilot burner 22 is lighted.

The safety valve 15 and ignition pilot burner 22 shown schematically in Fig. 'l are preferably embodied in an integral valve and lighter unit of thetype shown in U. 'S. patent application Serial No. 105,545 of Peter I. Hollman, filed July 19, 1949, since issued as Patent No. 2,649,904. The lighter unit supports an electric ignition coil 23 positioned to ignite gas issuing at the port 24 of the lighter unit, which in turn lights the ignition pilot .flame at 22 in the manner described in the aforesaid patent man application, the normally closed thermal switch is adapted to open in response to heat from the pilot flame at 24 after the latter has been lighted "by the ignition coil 23. When the thermal switch 25 opens in this manner it opensthe circuit for the ignition coil 23, with which it is connected in series, and thereby causesthe ignition coil to be de-energized. As more fully disclosed in the aforementioned patent to Hollman, the ball valve 18 is normally seated to block flow through the outlet passage 17. When the ignition pilot burner 22 is lighted, it heats a thermal responsive element 45 (see Fig. 3) which extends from a point adjacent the ignition pilot to a point adjacent the safety valve 15. A valveoperating finger 46 is pivotally mounted on a pin 47 and arranged to en- A bifurcated arm 48 is provided on the other end of the pin 47 and engages a pin 49 carried by the thermal responsive element to pivot the finger-46 and move the ball 18 off its seat when the thermal element is heated by the lighter unit there is provided a flow restricting orifice 33 which receives gas from the pilot line 28. The orifice 33 limits the amount of gas passing to the pilot burner and also causes back pressure to be built up in the pilot line 28.

As best seen in Fig. 2, the pressure switch 31 includes a chamber 34 which communicates through the fitting 30 withthe pilot line 28. A flexible diaphragm 35 extends acrossthe chamber 34 and is adapted to move upwardly in Fig. 2 in response to gas pressure in chamber asv ess 34 resulting from the back pressure in pilot line 28. At

its upper face the diaphragm 35 carries a dielectric pad 36 positioned to engage the flexible leaf spring support 37 for the movable contact 38 when the diaphragm is moved upwardly. The pressure switch also includes a fixed contact 39 located above the movable contact 3&5 and adapted to be engaged thereby when the diaphragm 35 is moved upwardly. The pressure switch is connected electrically in series with the ignition coil 23 across the 12 volt secondary of the transformer 40. The circuit for the ignition coil 23 includes, in series, the lead 64D, which extends from the high side of the secondary of transformer 40 to the pressure switch terminal 61, the fixed contact 39 of the pressure switch, the movable contact 38 and its support 37, the other terminal 62 of the pressure switch, the lead 63 from terminal 62 to one side of the ignition coil 23, the movable contact 27 of thermal switch 25 connected to the other side of the ignition coil, and the grounded fixed contact 26 of the thermal switch. Normally, with the oven control valve 12 closed and no back pressure in the pilot line 28, the pressure switch 31 is open and the ignition coil 23 is thereby tie-energized.

The solenoid valve 29 in the pilot line 28 is normally open, that is, when the solenoid coil at 41 is de-energized the valve 29 is open, as shown in Fig. 1, to permit the flow of gas through the pilot line 28. The solenoid coil 41 is connected electrically in series with a clock-controlled switch 42, which is under the control of a clock 43 mounted on the stove. The clock switch 42 and the solenoid coil 41 are connected in series across 115 volt house current line through the plug 44. The clock con trol circuit includes a lead 64 from one side of plug 44 to the solenoid coil, a lead 65 from the other side of the solenoid coil to the movable contact of switch 42, and a lead 66 from the fixed contact of switch 42 to the opposite side of plug 44. The clock 43 and clock switch 42 are of a conventional type in which the switch 4 2 is closed when the clock is pre-set to begin the cooking operation at a predetermined later hour and the switch 42 is automatically opened by the clock when the time arrives to begin the cooking operation of the oven.

In the operation of the system thus far described, initially the oven control valve 12 is closed and there is no gas supplied to either the oven burner line 14 or the pilot line 28, main burner safety valve is closed, pressure switch 31 is open, thermal switch 25 is closed, and ignition coil 23 is deenergized. If the clock control 43 is being used to start the oven at a predetermined time after the oven control valve is opened, then the clock 43 is pre-set in a known manner, which action closes switch 42 to energize solenoid 41 and close the solenoid valve 29. If the clock control is not to be used, then the clock switch 42 is in its normally open condition to maintain solenoid coil 41 de-energized and thereby to permit the solenoid valve 29 to be in its normally open position.

Assuming the solenoid valve 29 to be open, when the oven control valve 12 is opened gas is supplied through conduit 14 to the normally closed safety valve 15, which at this time is closed and thereby prevents gas from flowing to oven burner it Opening of the oven control valve 12 also supplies gas through pilot line 28 to the fuel passage 32 in the lighter unit, from which it passes to the pilot flame orifices at 24 and 22. The flow restriction orifice 33 causes back pressure to build up immediately in the pilot line 28 to close the pressure switch 31. Closing of the pressure switch 31 completes the energization circuit for the ignition coil 23, which becomes energized and ignites the gas issuing at the pilot orifice 24 and, in turn, the gas issuing at the ignition pilot orifice at 22 is ignited. Heat from the pilot flame at 24 then acts against the normally closed thermal switch 25 to open this switch and thereby deenergize the ignition coil 23 following the lighting of the ignition pilot burner. Likewise, the thermally responsive mechanism which controls the ball valve 18 in the oven burner safety valve 15 responds to heat from the pilot burner to open the safety valve 15 after the pilot burner has been lighted.

The gas issuing at the flame ports of the oven burner to is then ignited by the ignition pilot flame at 22.

If the clock control at 42, 43 is used, then the operation of the system is the same as above, except that the start of the ignition operation is delayed until the solenoid valve 29 opens, under the control of the clock switch 42, as described.

With the above-described system, the pressure switch 31 may be mounted on the back or side wall of the stove and there is no need to provide a protective sheath for the electrical leads from the plug 44 to the pressure switch. In prior electric ignition systems for oven burners, it was necessary to provide a switch in circuit with the ignition coil which was located at the oven control valve and which would close in response to opening of the oven control valve. This necessitated running the electrical leads to this switch through the burner box for the top burners on the stove and providing a liquid-proof shield around these leads, all of which complicated and increased the cost of installing and servicing such electric ignition systems on gas stoves. With this prior assembly it was also necessary to provide a set of knife disconnects in the line from the oven control switch to the ignition coil to facilitate installation and servicing of the ignition system. in addition, the oven control valves having such switches had to be specially designed for that purpose and were not interchangeable with oven control valves of the same general type but intended for stoves not having electric ignition for the oven. As contrasted with this, with the system of the present invention, there is no switch required at the oven control valve and any one of the wellknown standard oven control valves may be used on the present system as readily as on stoves not having electric ignition for the oven.

7 Where the clock control feature was used on prior electric ignition systems, it was necessary to provide an additional clock-controlled switch in circuit with the ignition coil, as well as the clock-controlled switch which controls the solenoid valve. This additional switch was necessary to insure that the ignition coil would be de-energized until the appropriate time determined by the clock, and not immediately upon opening the oven control valve. Because of this additional switch at the clock, the clock control was not interchangeable with clock controls used on stoves not having electric ignition of the oven. However, with the present invention no additional switch is necessary at the clock control since the solenoid valve is located in the pilot line ahead of the pressure switch, thereby insuring that the circuit for energizing the ignition coil cannot be energized until the time determined by v the clock control. Thus, the clock control for the electric ignition system of the present invention need not be of a special design but may be interchangeable with clock controls used on stoves not having electric ignition for the oven.

For broiler operation, the system of Fig. 1 is provided with a manually controlled broiler valve 50 mounted on the manifold lit to receive ga therefrom. The broiler valve has a main outlet communicating with a main burner conduit 51 leading to the inlet chamber 16 of. the safety valve 15 for the main burner 19. The broiler valve also has an auxiliary outlet communicating with a conduit 52 leading to the pilot line 23 and communicating therewith between the solenoid valve 22 and the fitting 30 for pressure switch 31.

For obvious reasons, due to the nature of the cooking operation involved, the broiler ignition circuit bypasses the While in the foregoing description and in the accompanying drawing there is disclosed a specific preferred embodiment of the present invention, it is to be understood that various modifications, omissions and refinements departing from the particular described embodiment of the invention may be adopted without departing from the spirit and scope of this invention.

Iclaim:

1. A control system for an oven burner arranged for manual and automatic operation comprising a gas supply line, a main oven burner, a pilot burner in igniting relation to said main burner, control valve means including a manually operable main shut-off valve communicating with the supply line and a temperature responsive flow regulating valve communicating with the shut-off valve, a main burner conduit communicating said main burner with said control valve means after said How regulating valve, said regulating valve being manually adjustable to a preselected temperature setting and adapted to open and close in accordance with the temperature in the oven to regulate the flow of gas to the main burner and maintain that preselected temperature in the oven, a pilot burner conduit communicating with said control valve means after said main shut-off valve and before said flow regulating valve, an electrically energized igniter for igniting the pilot burner, a normally open pressure switch in circuit with the igniter and including a pressure responsive movable element in communication with said pilot burner conduit and operative to control the operation of the pressure switch in accordance with the pressure in the pilot burner conduit, flow restriction means in the pilot burner conduit between the pressure responsive element and the pilot burner operative in response to opening of the main shut-off valve to build up back pressure in the pilot burner conduit means at said pressure responsive element to operate the pressure responsive switch and complete the energization circuit for the igniter, a normally closed safety valve means in the main burner conduit between the flow regulating valve in the main burner, said safety valvemeans including a valve member movable from a position blocking flow through said main burner conduit to an open position, means engageable with said safety valve member and operable in response to the heat produced by said pilot burner when the latter is ignited to move the safety valve member to its open position, a normally open valve means in the pilot burner conduit between the main shut-off valve 1 and the pressure switch for controlling the flow of fuel to the pressure responsive element and said pilot burner, electroresponsive valve actuating means adapted upon energization to close said valve means and prevent flow of gas to said pressure responsive element and said pilot burner when said main shut-oil? valve is opened, and a program switch means operable to energize and de-energize said valve operating means at preselected selectively variable times to effect a time controlled cooking cycle in which the valve means is opened to supply gas to the pressure responsive means and pilot burner and thereby initiate the cooking cycle and to thereafter close the valve means and stop the cooking cycle.

2. An oven burner control system comprising a gas supply line, a main oven burner, a pilot burner in igniting relation to the main lf-urner, control valve means including a main shut-off valve communicating with the supply line and a temperature responsive flow regulating valve communicating with the shut-off valve, a main burner conduit communicating said main burner with said control valve means after said flow regulating valve, said regulating valve being manually adjustable to a preselected temperature setting and adapted to open and close in accordance with the temperature in the oven to regulate the flow of gas to the main burner and maintain that preselected temperature inthe oven, a pilot burner conduit communicating with said control valve means after said main shut-oif valve and before said flow regulating valve, an electrically energized igniter for igniting the pilot burner, a normally open pressure switch in circuit with the igniter and including a pressure responsive movable element in communication with said pilot burner conduit and operative to control the operation of the pressure switch in accordance with the pressure in the pilot burner conduit, flow restriction means in the pilot burner conduit between the pressure responsive element and the pilot burner operative in response to opening of the main shut-01f valve to build up back pressure in the pilot burner conduit means at said pressure responsive element to operate the latter to close the pressure responsive switch and complete the energization circuit for the igniter, a normally closed safety valve means in said main burner conduit between the flow regulating valve and the main burner, said safety valve means including a valve member movable from a position blocking flow through said main burner conduit to an open position, means engageable with said safety valve member operative in response to the heat produced by said pilot burner when the latter is ignited to move the safety valve member to its open position, normally open valve means in the pilot. burner conduit between the main shut-01f valve and the pressure switch for controlling the flow of fuel to said pressure responsive element and to said pilot burner, electro-responsive valve actuating means adapted upon energization to close said valve means to prevent the flow of gas to said pressure responsive element and to said pilot burner when said main shut-oif valve is opened, and switch means for selectively energizing said valve actuating means.

References Cited in the file of this patent UNITED STATES PATENTS Hollman Aug. 25, 

